I received the vol. 1 book a couple months ago. I like the book but there are several problems that I could not solve. Could anyone offer help? Here are the pictures that I have solved so far (which are in page 97, 125, 138 and 198 respectively), thanks!

To get this, I noticed that your grid only had two alternatives for HOPN and pharma. Clue 1 says that HOPN and pharma cannot be in the same row, so there are only two alternatives for that pair. To save time, I just chose .75 for HOPN to see what would happen, and it led to a "solution."

Then I checked that result against the clues, and it seemed consistent.

I was expecting to get either a conflict or a bunch of empty rectangles that usually mean a mistake was made somewhere. If I got one of those results, I would have just chosen the other alternative for HOPN and pharma.

Does the book state somewhere that each solution is unique and each step in the solution only requires logic (no guess-and-check)?

If the puzzles in the book are like the ones in the online library, there should be a way to deduce the next step without guessing.

Does the book state somewhere that each solution is unique and each step in the solution only requires logic (no guess-and-check)?

If the puzzles in the book are like the ones in the online library, there should be a way to deduce the next step without guessing.

According to the Introduction, it says:

Every puzzle in this book is solvable through logical deduction alone; trial and error and "forward guessing" are never required for a successful solve, though you are welcome to use these methods if you like!

It seems that some of the problems may have more than one solution or cannot be solved. I don't know if it happens or I miss something during solving the problems.